Formation control of underwater mobile sensing networks

Formation control is essential for an underwater mobile sensing network (UMSN), and an ad hoc network which wirelessly connects underwater vehicles of sensing and/or observing types via acoustic communications, to fulfill mobile sensing tasks. The problem of formation control for a UMSN with varying topology is studied in this paper. The methodology of synthesizing distributed formation controller which stabilizes a UMSN with varying topology is proposed on the basis of the stability analysis of linear time-varying systems.     

基于多参数加权的IVC网络系统移动自适应分群算法研究

由于IVC车辆间通信系统中车辆的移动性,其无线通信网络的拓扑结构是动态变化的.若每个车辆节点各自维护网络路由信息会导致大量的控制信息而占用带宽资源,因此需要将IVC网络内的车辆节点进行分群处理.文中提出了一种针对IVC网络系统的基于多参数融合加权的改进移动分群算法,该算法将节点的位置及速度等运行状态信息作为决定分群的因素,并考虑了车辆节点的移动特性,因此保证了网络分群的稳定性和移动适应性.     

An range-free localization scheme for large scale underwater wireless sensor networks

In this paper, we study an area localization problem in large scale underwater wireless sensor networks (UWSNs). The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver (DET) and 3D multi-power area localization scheme (3D-MALS) to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme (2D-ALS) and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.     

Simultaneous localization and mapping of autonomous underwater vehicle using looking forward sonar

A method of underwater simultaneous localization and mapping (SLAM) based on on-board looking forward sonar is proposed. The real-time data flow is obtained to form the underwater acoustic images and these images are pre-processed and positions of objects are extracted for SLAM. Extended Kalman filter (EKF) is selected as the kernel approach to enable the underwater vehicle to construct a feature map, and the EKF can locate the underwater vehicle through the map. In order to improve the association efficiency, a novel association method based on ant colony algorithm is introduced. Results obtained on simulation data and real acoustic vision data in tank are displayed and discussed. The proposed method maintains better association efficiency and reduces navigation error, and is effective and feasible.     

面向多层级目标的汽车前围声学包优化研究

为了研究汽车声学包设计参数对其多性能目标的影响,首先,改进了传统的深度信念网络（DBNs）方法,并提出SVR-DBNs (support vector regression-deep belief networks)模型,提升了模型映射的准确度;其次,从车辆噪声传递关系与层级目标分解角度出发,提出了一种多层级目标预测与分析方法;最后,将所提方法应用于具体车型的前围声学包性能、重量与成本多目标预测与优化分析.研究结果表明：SVR-DBNs方法对前围声学包性能、重量与成本目标预测准确度均在0.975以上,优于传统的反向传播神经网络（BPNN）、SVR与DBNs模型;基于SVR-DBNs模型的优化结果与实测结果接近,两者加权目标相对误差为1.09%（平均传递损失（MTL）、重量和成本相对误差绝对值分别为1.44%、1.04%与0.71%）,优化后的实测结果较前围声学包原始状态性能、重量和成本分别提升了5.51%、9.01%与4.40%.     

一种分布式Ad hoc网络广播算法

在无线Ad hoc网络中,广播作为一种重要的通信方式被许多单播和多播协议用来完成其路由建立和维护工作.文中假设网络中所有的移动节点共享信道,并且节点不知道全局网络拓扑信息.因此网络中每个节点只能通过洪泛进行通信.但是采用洪泛方式广播,由于每个节点都要向其相邻节点转发报文,协议效率低、通信代价昂贵,而且还会带来广播风暴问题.为避免由于洪泛造成的广播风暴问题,文中提出一种分布式Ad hoc网络广播算法.该算法无需任何控制报文.算法简单易行,适合移动无线网络环境.仿真实验结果表明新的算法与现有算法相比更加有效和健壮.     

A Distributed Authentication Algorithm Based on GQ Signature for Mobile Ad Hoc Networks

Introduction Mobile ad hoc networks (MANETs) are newinfrastructureless networks without the usual rout-ing infrastructure like fixed routers and routingbackbones. A mobile ad hoc network is a multi-hop temporary self-organizing system compromisedof a group of mobile nodes with radios. MANETshave some special characteristics: self organizing,dynamic topology, limited bandwidth, resourceconstraint nodes, multi-hop routing, vulnerable tosecurity attacks etc. Recently, MANET has beenone of t…     

A Layer-Cluster Key Agreement Protocol for Ad Hoc Networks

Mobile ad hoc networks create additional challenges for implementing the group key establishment due to resource constraints on nodes and dynamic changes on topology. The nodes in mobile ad hoc networks are usually low power devices that run on battery power. As a result, the costs of the node resources should be minimized when constructing a group key agreement protocol so that the battery life could be prolonged. To achieve this goal, in this paper we propose a security efficient group key agreement protocol based on Burmester-Desmedt (BD) scheme and layer-cluster group model, referred to as LCKM-BD, which is appropriate for large mobile ad hoc networks. In the layer-cluster group model, BD scheme is employed to establish group key, which can not only meet security demands of mobile ad hoc networks but also improve executing performance. Finally, the proposed protocol LCKM-BD are compared with BD, TGDH (tree-based group Diffe-Hellman), and GDH (group Diffie-Hellman) group key agreement protocols. The analysis results show that our protocol can significantly decrease both the computational overhead and communication costs with respect to these comparable protocols.     

方格路网车辆路径在线选择模型及竞争分析

为分析城市方格路网遭遇突发性堵塞下的车辆路径选择问题,应用在线问题与竞争策略的方法建模,设计了2种在线路径选择竞争策略,即方向贪婪策略和多选择移动策略,计算了2种策略的竞争性能比。通过策略竞争分析得出:在发生突发性堵塞的情形下,方向贪婪策略下的费用为最优费用的3倍;利用多选择移动策略在对网络具有实际意义约束条件下的部分情形能够得到最优费用,且在最坏情形下的费用为最优费用的2倍;2种策略的竞争性能比优于以往研究给出的堵塞不可恢复问题竞争比的下界。     

一种基于移动台位置的动态定位算法

根据检测电波到达时间（TOA）的定位法提出了一种基于移动台位置的动态定位算法。该算法利用蜂窝网络系统中多个基站检测到的移动台电波TOA信息对移动台进行定位估计,参与定位估计的基站数目及其定位算法中相应的权值随移动台与服务基站的距离自动动态改变。计算机模拟结果表明,该算法在3种典型移动通信信道环境中都能得到较好的定位效果。     

基于移动代理的分布式无线传感器网络管理

无线传感器网络正日益成为一种用于各类应用中的重要技术。无线传感器网络由成百上千个传感器结点构成,这些传感器结点具有传感、处理及无线通信的能力。但迄今为止,无线传感器网络及其应用在发展的同时,并未考虑对无线传感器网络管理的解决方案。作为一种动态拓扑的无线移动网络,相对于常规网络的管理而言,无线传感器网络的管理有它自身的特点和要求。本文首先分别介绍了无线传感器网络以及移动代理的基本概念和特点,分析研究了无线传感器网络管理的自身特点和需求。然后在此基础上,提出了一种基于移动代理的分布式无线传感器网络管理的体系结构,其中包括网络管理体系结构的工作原理,以及被管理的传感器结点的结构模型。最后讨论研究了在此网络管理体系结构中的传感器结点的分簇要求及特点。     

一种有效的水声信道盲均衡算法

针对超指数迭代判决反馈盲均衡（SEIDFE）算法在水声通信系统中表现出的收敛性差的问题,提出了一种稳健性好、收敛快的双模式超指数迭代判决反馈盲均衡算法.该算法对均衡器输出的实部和虚部分别进行非线性变换以修正误差控制信号,从而纠正载波相位旋转;在此基础上,将一种新的自适应变步长算法应用到前馈滤波器前向权值的迭代步长中,提高算法收敛速度;并采取判决误差切换准则,将上述改进算法与判决导引算法有机结合起来,提高算法稳健性和收敛性能.仿真结果证明了该算法的有效性.     

机车车辆动态模拟和台架试验

分析了动态模拟技术,包括实物模拟、计算机模拟和混合模拟,在机车车辆研制过程中的重要作用,给出了模拟技术和对象以及研究内容之间的相互关系。通过计算机模拟对机车车辆方案进行仿真分析来优化结构和悬挂参数,用实物模拟或混合模拟研究零部件服役性能,采用全尺寸试验台架对机车车辆样机进行运行模拟,以确定其运行性能。给出了计算机模拟的步骤、实物模拟应遵循的相似原则和混合模拟的实施方法,探讨了机车车辆台架试验方法和试验分类,以及台架试验的应用情况,介绍了牵引动力国家重点实验室研制的机车车辆整车滚动振动试验台和综合参数测定试验台的主要技术指标和功能。     

Optimal energy management for a complex hybrid electric vehicle: Tolerating power-loss of motor

The energy management may perform well under normal conditions, but may lead to poor behavior under abnormal situations. To tackle this problem, an optimal control strategy called rule-based equivalent fuel consumption minimization strategy (RECMS) is developed for a new complex hybrid electric vehicle (CHEV).It optimizes the energy efficiency and drive performance to cater for normal and power-loss operations of the tractive motor. Firstly, the strategy formulates a novel objective function based on the equivalent fuel concept.By accounting for the actual fuel cost, the equivalent fuel cost for the electric machines and virtual fuel cost for the drivability, the cost function is obtained. Furthermore, some penalty factors are presented to optimize the performance target. Finally, experiments for a practical CHEV are performed to validate a simulation model.Then simulations are carried out for both rule-based and RECMS. The results show that the optimal energy management is working well.     

基于 Arduino 的车载监控终端设计

为实现智能手机对车辆的实时定位、控制,设计一款车载移动监控终端。终端采用开源硬件A rduino作为主控制器,同时利用GPS、GPRS、CAN等模块,采集并处理定位数据及车辆状态等信息,并上传到通信服务器。智能手机端可获取服务器上的信息并发送控制命令至服务器后返回到车载端的主控制器,主控制器根据命令执行相应操作,从而实现对车辆的实时控制。     

大深度水下航行体引起的水底压力变化

水下航行体引起的水底压力变化是航行体的重要目标特性之一,可用于水下运动目标探测和水中兵器研制.基于船舶水动力学势流理论,建立了水下航行体水底压力计算模型.利用HessSmith方法,对大深度水下航行体的压力场分布进行了计算,分析了航行体水压场沿纵向和潜深的变化规律,计算结果和实验结果有较好的一致性.     

回转体尾部形状对导管螺旋桨的水动力性能影响分析

不同的水下航行器尾部线型的差异不仅会表现出自身不同的水动力性能,而且由于尾部线型的不同,也会引起尾部螺旋桨附近的流场发生变化,进而影响螺旋桨的推力性能.本文以尾部安装了导管螺旋桨的Myring型回转体水下航行器组合模型为分析对象,以计算流体力学为手段,通过调整回转体线形的控制参数尾部离去角来改变尾部外形,计算了不同航速下,4个不同尾部外形的回转体阻力与设置在回转体尾部的导管螺旋桨推力状态的变化,分析了尾部曲线形状对于导管螺旋桨推力性能的影响,并结合回转体自身的水动力性能变化,针对不同航速下的回转体尾部线型的选取提出了优选方案.     

多约束条件下城市道路环卫车优化配置与路径规划

为有效解决当前城市环卫车调度决策过度依赖人工主观经验造成的车辆配置不合理和作业效率低下问题,本文提出一种多约束条件下的城市道路环卫车优化配置与路径规划方法。通过综合考虑环卫车在现实作业中的作业时限、服务次数、行驶速度和车辆退出节点等多种约束条件,将物理道路网络拓展为时空网络,刻画车辆在路网上的时空运行轨迹,进而将环卫车优化配置与路径规划问题从数学上描述为带多类约束条件的弧路径问题(Arc Routing Problem, ARP)。 在此基础上,构建以车辆配置与出行总成本最小化为目标函数的环卫车优化配置与路径规划模型,并通过设计分支定价算法精确求解模型。将所提方法应用于苏州工业园区19个区域路网的环卫车辆配置与调度管理,从经济成本、作业效率和环保效益这3方面评估所提方法的可行性和有效性。结果表明：本文所提方法能够显著节约环卫运营成本,提升环卫车辆作业效率;同时,可有效降低环卫车辆碳排放量,形成良好的经济和社会效益,为智慧环卫提供了行之有效的新方案。     

Multi-channel spectrum sensing in cognitive ad-hoc networks: An energy-efficient manner

Cognitive radio,which is capable of enabling dynamic spectrum access,is a promising technology in future wireless communication.The feasibility of cognitive radio network greatly depends on the energy efciency and reliability of spectrum sensing technology.In this paper,spectrum sensing in cognitive ad-hoc network（CAN）with wide-band dynamic spectrum is considered.A cognitive cluster head（CCH）is set and responsible for dividing the wide-band spectrum into multiple sub-channels;it can either sense sub-channels in a centralized manner,or make use of sensing modules to sense sub-channels in a distributed manner.Then cognitive users（CUs）can get sensing results and access to the available sub-channel.We take the cost of control message into consideration and formulate the energy consumption of CAN in terms of sub-channel sampling rate and whole-band sensing time.We define energy efciency intuitively and solve the energy efciency optimization problem with sensing reliability constraints by constructing a parametric problem and obtain the optimal sampling rate and the wholeband sensing time.Power dissipation model of a practical A/D convertor（ADC）is introduced,and numerical results are given to show the energy efciency performance of two diferent sensing manners.     

城市地下快速路减少机动车尾气污染的环境效益模型

城市地下快速路处在一个封闭的环境中,机动车尾气可通过高技术措施进行集中过滤和处理。为了量化建设城市地下快速路产生的减少尾气污染的环境效益,首先利用单车污染物排放因子法,量化了单位时间、单位长度城市地下快速路上,各类型车辆的排放物中CO、HC、NOx三种气体污染物各自的强度。确定了污染物排放因子车速订正系数公式和系数的取值。为了将减少气体污染的效益直观化,通过在尾气控制技术措施的花费与经技术处理后污染物的减少量之间建立关系,取得单位三种气体污染物的处理成本,建立了单位时间内,地下快速路建设项目分别减轻三种气体污染物的效益量化模型。此外,对缓解城区CO2气体的热污染所产生的环境效益,也建立了量化模型,并最终得到了城市地下快速路对于减少汽车尾气对环境污染的效益模型。